This invention relates to a method for making a cylinder liner for liquid-cooled engines, on the outer-surface of which, a bandlike sealant is applied. More particularly, it relates to a method of making a sealant-banded cylinder liner wherein said sealant comprises two-layer laminate of completely cured and half cured silicone resins.
As shown in FIG. 1, in liquid-cooled engines such as diesel engines, a cylinder liner 3 is generally inserted into a cylinder bore 2 of a cylinder block 1 so as to form a water jacket 4 for cooling water between the block 1 and the liner 3. In such engines, two O-rings 6 and 6' are set in recesses on a protruding wall 5 of the cylinder bore 2 and they seal the water jacket to prevent leaking of cooling water into an oil pan (not shown).
The cylinder liner 3 of such engines tends to bulge due to the combustion pressure of fuels during its operation, or vibrate intricately in the cylinder bore 2 due to reciprocating motions of the pistons. Then, cavitations occur in the cooling water of the water jacket 4, which lead to fatigue failures of the liner 3 and accelerate its corrosion. If the cylinder liner 3 is corroded markedly, it shows poor mechanical strength and short lifetime. Especially, the narrower a clearance 7 between the protruding wall 5 in the bore 2 and the cylinder liner 3, the more cavitations develop. Hence, it is corroded severely.
Further, O-rings 6 are worn out by vibrations of the cylinder liner 3, and then the cooling water in the water jacket 4 possibly leaks into the oil pan or a crank case (not shown).
Heretofore, a sealant 8 (FIG. 2) such as synthetic resins, in addition to these O-rings, has been filled into the clearance 7 around its entrance part to prevent cavitations and the cooling water leakage, in order to improve the above mentioned disadvantages. In such prior art, for example, a sealant is forced into a channel (not shown) slotted on the outer surface of the liner 3, or is sprayed onto the inner surface of the cylinder block 1 to form a sealant band thereon by means of an air-gun.
However, according to these methods, it takes a longer time to apply the sealant or it is difficult to obtain sufficient adherence between the sealant and the cylinder block or the cylinder liner. Thus, desirable sealing effects can not be attained by these known methods.